US2445674A - Pneumatic nail driver - Google Patents

Description

July 20, 1948. r w. E. KENDALL 2,445,674

' ruzumncmn DRIVER Filed March 3, 1945 2 Shee'tS-Sheet 1 Patented July 20, 1948 PNEUMATIC NAIL DRIVER Willard E. Kendall, Fltehburg, Mass.

. Application March 3, 1945, Serial No. 580,778

6Claims. 1

This invention relates to a nailing machine,

which is constructed with means for nailing by the air operation of the driving hammer or ram, and with means for feeding nails spaced apart on a fragile or easily breakable paper or plastic strip to the driving hammer or ram.

One of the objects of the invention is to provide an automatic feeding hand carried nailing machine, which will continue to operate under air or other similar pressure, to successively drive nails into worlr, by the manual pressure of a release valve.

Another object of the invention is the provision of a machine of this type with a nail strip track, and air channels so located that the nails are advanced along this track to driving position, by the impulse action of released air.

With the above and other objects in view the invention consists in certain new and useful constructions, combinations and arrangements of parts, clearly described in the following specification, and fully illustrated in the accompanying drawings, in which:

Fig. 1 is a side elevation of the chine.

Fig. 2 is a top plan view thereof.

Fig. 3 is a detail vertical sectional view, taken on line 3-3 of Fig. 1, looking in the direction of the arrows.

Fig. 4 is a central, vertical and longitudinal sectional view, taken on line 4-4 of Fig. 2, looking in the direction of the arrows.

Fig. 5 is a detail perspective view of a nail trap and guide.

Referring to the accompanying drawings which are illustrative of the practical design by which the invention is carried out, 5 designates a frame casting, which is constructed to provide a vertical cylinder 6, having a liner 1, for the piston 8. This piston is equipped with a detachable head disc 9, which is secured in place by means of the screw N, which is retained by lock washer II. This disc 9 holds the packing washer ll against the head of the piston, to prevent leakage along the sides of the piston.

The piston carries a ram or hammer rod l2,

improved mawhich is coupled thereto by screw threads, and

the lower end of this rod slides in the ram or hammer guide passage l3, formed in axial alignment with the cylinder 8. A coiled compression spring I! surrounds the hammer rod It with its upper end engaging a iocknut I! which serves to lock the piston on the "rod II. The opposite end of the spring I seats on the bottom wall of a spring well I! formed in the frame immediately beneath the cylinder 5. The upper end of the cylinder is closed by a cap it, secured in place by screws 18, and sealed by the gasket 20. This cap also serves to hold the cylinder liner in place.

Nails are fed to the ram or hammer rod guide passage l3 along the horizontal track 2|, which is shown to be disposed at right angles to the vertical axis of the ram or hammer rod. The nails 22 are arranged on a carrier strip 23 of easily breakable plastic or paper or other material, and a plate 24 is detachably. secured to the bottom of the frame to close the longitudinal opening below the track and its strip of nails.

The entire track may be removed by the withdrawal of the dowel pins 25 and other tracks substituted for the accommodation of nails of different sizes.

The frame includes the upper horizontal bar 26, which has an air feed passage 26a which communicates with the air pressure chamber 21 above the piston, through the inlet port 28 in the wall of the liner and the wall of the cylinder, which port is never closed by the return movement of the piston, under the reaction'of its spring. Formed in the bar 26 is a recess 26 which intersects the air feed passage 26a and opens through the top side of the bar 26. The open end of the recess 26' is somewhat enlarged and internally screw-threaded for a purpose to be more fully set forth. Flow of air through the air feed passage 26a is controlled by means of a manually operated-button valve unit designated generally 29, which is seated in the recess 26' as shown in Figure 4.

This button valve unit 29 comprises a bushing or thimble 32 in which a valve piston 2! slides longitudinally. Seated on the bottom wall of the thimble 32 is a compression coiled spring 30 the opposite end of which bears against the innermost end of the valve piston 29 to normally urge it outwardly through the open end of the thimble. Formed in the side wall of the valve piston 29 intermediate its ends is a longitudinally extending groove 29" into which a pin 29'" extending radially through the side wall of the thimble projects was to retain the valve piston therein for limited movement. Intermediate the ends of the thimble are aligning openings 32a which align with the air feed passage 25a. Extending transversely of the valve piston on'an axis' perpendicular to the pin 29" is a passage 29a which when the valve piston is pressed inwardlyagdi'nst the spring ill aligns with the openings fua to establish communication between the air feed passage 26a and the inlet port 28. As previously stated the button valve unit 29 is received in the recess 26', a sealing gasket 34 is then inserted to rest upon the end of the thimble 32 and an externally screw-threaded ring nut 38 is entered into the threaded end of the recess to hold the valve unit 29 in place and effectively seal the whole against air. leakage.

From the passage 26a, forwardly of the valve unit 29, a vertical relief air passage 35 is formed, which leads through the frame. to the track 2|, and which discharges air directly against the strip nails through the forwardly and downwardly deflected outlet 35a thereof, near the discharge forward end -of this track 2i. Another air relief opening or passage 38 leads from the bottom of the cylinder to this outlet 35a. Another relief air passage 31 leads from the wall of the liner and the cylinder, midway of the same. to the air relief passage 35.

When air is released by the manual operation of the button valve, the air will flow downwardly through the passage 35 and out through the outlet 35a, thus tending to hold the carrier strip forwardly and the foremost nail in the path of the hammer. As the piston descends air will be forced out of the cylinder into the passage 35, to further augment the holding effect. As the hammer descends it will first encounter the nail head of the foremost nail in the strip and after driving the nail through the strip will shear that portion of the strip lying in its path from the remainder of the carrier strip and carry the sheared portion against the work as the nail is driven home. Having driven the nail home, pressure on the button valve is released thus cutting off the supply of air pressure to the piston through the passage 28a. The piston 8 and hammer l2 then return to retracted position under the influence of the spring ll. The air remaining in the chamber 21 behind the piston i2 is displaced by such movement of the piston and flows through the port 28 into the passage 35 to be directed against the carrier strip 23 to cause it to move and advance the next successive nail into the path of the hammer ready for a repeat operation. It is to be understood of course that the distance between the nails and the strip 23 is equal to the diameter of the hammer so that as the strip lengths are sheared off, the

nails will be brought 'in succession into axial alignment with the hammer.

From the rear or inlet side of the main air feed passa e 26a an air passage 38 leads to the track 2|, rearwardiy of the discharge port or outlet 35a. The flow of air through this passage may be controlled by means of a manual valve 39. By operating this valve the air flow may be regulated or stopped and the air flowing through this passage 38 will serve to aid in holding and advancing the carrier strip 23.

The frame is constructed with an integral nail discharge tube or guide 40, and in the bore of this tube or guide a nail restraining member 4| is secured, as by the screw pins 42. This guide or member is provided with a series of radially yielding fingers 43, which may be made ofgrubber or spring metal, and which are adapted to' yield outwardly under the driving force of the ram or hammer rod, when air pressure is applied thereto. The nail restraining member also serves as a guide to direct the nail straight into the object.

Air is supplied to the main air feed passage 28a by means of the air conduit M, which is coupled thereto, by the bushing 45.

By succesively operating the manual valve nails may be successively driven from the nail strip, as the air not only drives the ram or hammer rod, but also advances the nail strip so that there is always a nail under the ram or hammer rod. This ram or hammer rod is formed with a hardened concave driving nose so that a shearing force will be applied to the plastic carrier strip when the hammer descends.

The entire frame may be constructed oi aluminum or magnesium, or other light materials, and the various passages are constructed by the usual coring methods used in casting operations.

Various changes in the details of construction, their arrangement and combination, may be resorted to, within the scope of the claims forming part of the patent which may be granted on this application.

Having described my invention, I claim as new:

1. In a nailing machine, a pneumatically advanced reciprocable hammer, yielding means to retract said hammer, means to guide a carrier strip along a path which lies perpendicular to the hammer, said carrier strip being adapted to support a plurality of nails in spaced relation with their axes parallel to the axis of the hammer, means to admit air under pressure behind the hammer to advance it against the force of the yielding means and drive it against a nail carried by the carrier strip, and means to direct an air blast against the carrier strip to move it, and advance the next successive nail carried thereby into a position to be struck by the hammer.

2. In a nailing machine, a pneumatically advanced reciprocable hammer, yielding means to retract said hammer, means to guide a carrier strip along a path which lies perpendicular to the hammer, said carrier strip being adapted to support a plurality of nails in spaced relation with their axes parallel to the axis of the hammer, means to admit air under pressure behind the hammer to advance it against the force of the yielding means, and drivedt against a nail carried by the carrier strip, and means to direct air exhaust upon the return stroke of the hammer against the carrier strip to advance it and move the next successive nail into a position to be struck by the hammer.

3. In a nailing machine, a cylinder, 9. piston operable in the cylinder, a hammer carried by the piston, yielding means to normally hold the piston and hammer in retracted position, means to guide a carrier strip across the path of the hammer, said carrier strip being adapted to support a plurality of nails in spaced relation for successive presentation to the hammer in a position to be driven into work by the hammer, means to admit fluid under pressure into the cylinder to drive the piston and hammer against the pressure of the yielding means, and means to direct an air blast against the carrier strip to move it and advance the next successive nail into the path of the hammer.

4; In a nailing machine. a pneumatically advanced reciprocable hammer, yielding means to retract said hammer, means to' guide a carrier strip along a path which lies perpendicular to the hammer, said carrier strip being adapted to support a plurality of nails in a position parallel with the direction of movement of the hammer,

retract said hammer means to guide a carrier strip along a path which lies perpendicular to the path of the hammer, said carrier strip being adapted to support a plurality ofnails in spaced relation with their axes parallel to the axis of the hammer, means to admit air under pressure behind the hammer to advance it against the yielding means and drive a nail held by the carrier strip, and means to direct an air blast against the carrier strip upon retraction of the hammer to advance the strip and move the next successive nail into the path of the hammer.

6. In a nailing machine, a pneumatically advanced reciprocable hammer, yielding means to retract said hammer, means to guide a carrier strip along a path which lies perpendicular to the path of the hammer, said carrier strip being adapted to support a plurality of nails in spaced relation with their axes parallel to the axis of the hammer, means to admit air under pressure 15. Number behind the hammer to advance it against the yielding means and drive a nafl held by the carrier strip, and means upon the return stroke of the hammer to direct exhausted air against the carrier strip to advance it and move the next succesive nail into a position to be struck by the hammer.

WILLARD E. KENDALL.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Name Date 565,074 Goddu Aug. 4, 1896 1,703,458 Rufl Feb. 26, 1929 1,753,499 Burger Apr. 8, 1930 1,841,217 Seizer Jan. 12, 1932 20 1,980,967 Moody Nov. 13, 1934 FOREIGN PATENTS 7 Number Country Date I 568,718 France Mar. 31, 1924

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